1. Field of the Invention
The invention relates in general to an electronic device, and more particularly to a computer system and a power management method thereof.
2. Description of the Related Art
High-end notebook computer can use a voltage turbo boost (VTB) function of a smart charger to control the battery to provide power. After the VTB function is enabled, if system total power consumption is larger than a system constant power, the notebook computer can be powered by an AC adapter and the remaining power shortage can be powered by the battery.
Due to cost consideration and the popularity of the VTB function, the design and choice of AC adapter are directed towards slimness and lightweight. If the rated capacity of an AC adapter is too small, the AC adapter cannot enable a smart charger. A corresponding enabling input current is required to enable the VTB function. For example, when the AC adapter has a constant power of 40 W and an output voltage of 19V, the power protection point is equal to 90% of the constant power of the AC adapter (that is, 36 W). The VTB function has a minimum enabling current of 2 A. To enable the VTB function, the power protection point must be increased to 38 W (19V×2 A=38 W) from the original level of 36 W. However, if the remaining capacity is too low or the battery experiences an aging phenomenon caused by a long duration of use, the power requirement will not be satisfied. Meanwhile, when the computer system has a system total power consumption larger than the constant power of the AC adapter, the computer system may experience an abnormal shut down.